The invention pertains to a rotationally symmetrical tool carrier that can be separably connected to a rotary drive, with a tool receptacle surface for receiving at least one grinding and/or polishing element, with a fiber reinforcement that consists at least partially of natural fibers, and with a binder for stabilizing the natural fibers. The invention also pertains to a woven fabric carrier for woven grinding and polishing fabrics, a woven grinding and polishing fabric and a blank for the aforementioned objects. The invention furthermore pertains to a method for manufacturing a tool carrier, a grinding or polishing tool, a woven fabric carrier and a blank of the previously described type.
A fiber-reinforced rotationally symmetrical tool carrier of this type can be separably connected to a rotary drive and contains a tool receptacle surface for receiving at least one grinding and/or polishing element.
In a material processing tool with a fiber-reinforced rotationally symmetrical tool carrier that can be separably connected to a rotary drive and contains a tool receptacle surface, at least one grinding and/or polishing element is received on the tool receptacle surface.
The rotationally symmetrical tool carrier may, for example, consist of a circular disk or a cylindrical roller.
The material processing tool may, for example, consist of a fan-type grinder, fan-type grinding brushes or rollers, rough-grinding wheels, cutting-off wheels, polishing wheels, etc.
Material processing tools of this type are used in instances in which the surfaces of arbitrary materials need to be processed, smoothed, polished and/or modeled. Generally speaking, this pertains to instances in which material needs to be removed from a workpiece. These tools are expendable parts that are manufactured and used in large quantities.
Material processing tools that consist of a rotationally symmetrical tool carrier, to which grinding and/or polishing elements are attached, are sufficiently known. The grinding and/or polishing elements may, for example, consist of felt-type polishing elements, grinding or polishing fleeces, woven grinding fabrics and the like.
In known material processing tools, the tool carrier is compactly manufactured from plastic such that it is rigid and resistant to bending, wherein fiber reinforcements, for example, glass fiber reinforcements, are also used. When using such material processing tools, the generated frictional heat may cause a significant temperature increase. This also increases the temperature of the tool carrier such that its rigidity and consequently its mechanical stability are reduced.
Based on these circumstances, the present invention aims to disclose objects of the initially described type, as well as a method for manufacturing said objects, wherein these objects can be easily manufactured, have favorable mechanical and thermal properties and, in addition, be harmlessly disposed of.
In a rotationally symmetrical tool carrier, this objective is attained due to the fact that the binder consists of polyurethane, polypropylene, phenol resin, epoxy resin or biological polymer.
In a woven fabric carrier for woven grinding and polishing fabrics and in a woven grinding or polishing fabric, as well as in a grinding or polishing tool with embedded abrasive grain, the objective of the invention is attained due to the fact that the respective object is at least partially manufactured from natural fibers.
It is particularly advantageous that the respective binder consist of lignin or be based on corn starch.
In a woven fabric, the objective of the invention is attained due to the fact that the natural fibers consist of one or more of the materials hemp, flax or sisal. Sisal, in particular, is very resistant to abrasion such that it generates an abrasive effect if the tool, woven fabric or woven fabric carrier manufactured thereof is used for grinding purposes.
According to one preferred additional development of the tool carrier, the woven fabric carrier and the woven fabric, the respective object is manufactured from a granulate that consists of natural fibers and a binder.
In a blank that is additionally processed into a tool carrier, a tool, a woven fabric carrier or a woven fabric of the aforementioned type, the objective of the invention is attained due to the fact that the respective object is manufactured from a fiber mat that consists at least partially of natural fibers and contains a binder for the natural fibers.
According to one preferred additional development of the blank, the blank is manufactured from at least two layers of a fiber mat that consists at least partially of natural fibers and contains a binder for the natural fibers, wherein the layers are placed on top of one another in a sandwich-like fashion and bonded to one another.
According to another preferred embodiment of the blank, abrasive grain is applied onto the surfaces of the fiber mats before the bonding process.
In a method for manufacturing a tool carrier, a grinding or polishing tool or a blank, the objective of the invention is attained due to the fact that a pulp consisting of natural fibers and a binder is produced, the fact that plate-shaped basic elements are produced from the pulp, the fact that the basic elements are compressed and shaped by means of a pressing tool in such a way that several blanks are formed adjacent to one another, and the fact that the blanks are subsequently punched out.
According to one advantageous additional development of this method, abrasive grain is added to and homogeneously distributed in the pulp such that the abrasive grain is uniformly distributed in the objects manufactured therefrom.
In a method for manufacturing a tool carrier, a grinding or polishing tool or a blank, the objective of the invention is alternatively attained due to the fact that a pulp of natural fibers is produced, the fact that mat-like basic elements are produced from the pulp, the fact that the basic elements are sprayed with a binder, the fact that the basic elements are compressed and shaped into a blank by means of a pressing tool, and the fact that the blank is subsequently punched out.
According to one preferred additional development of the method for manufacturing a tool carrier, a grinding or polishing tool or a blank, several layers are, after being sprayed, bonded together in a sandwich-like fashion such that a basic element is formed.
In the method for manufacturing a tool carrier, a grinding or polishing tool or a blank, it is particularly advantageous that the spraying process be carried out with a binder that is heated to a temperature between 100 and 200xc2x0 C., preferably 150xc2x0 C.
The method for manufacturing a tool carrier, a grinding or polishing tool or a blank is preferably carried out in such a way that the compressing process takes place at room temperature. Alternatively, it may be practical to carry out the compressing process at a temperature between 100 and 200xc2x0 C.
For the method for manufacturing a tool carrier, a grinding or polishing tool or a blank, it is especially preferred that the blank be hardened for one to two days.
According to one preferred additional development of the method for manufacturing a tool carrier, a grinding or polishing tool or a blank, the fiber mat has a weight of approximately 1100-1500 g/m2 and a thickness of approximately 2.5-4 mm in the compressed state.
According to another advantageous embodiment of the method for manufacturing a tool carrier, a grinding or polishing tool or a blank, the mat-like basic elements are needled before they are sprayed. The term needling refers to needles acting upon the mat such that its surface is broken open.
According to another additional development of the method for manufacturing a tool carrier, a grinding or polishing tool or a blank, the compressing process is carried out with a pressure between 15 and 35 bar.
In a fiber-reinforced rotationally symmetrical tool carrier that can be separably connected to a rotary drive and is provided with a tool receptacle surface for receiving at least one grinding and/or polishing element, the invention proposes that the fiber reinforcement consist at least partially of natural fibers.
Accordingly, the invention proposes that the tool carrier of the previously described material processing tool be manufactured at least partially from natural fibers.
In addition, a rotationally symmetrical blank for being additionally processed into a tool carrier according to the invention is manufactured from a fiber mat that consists at least partially of natural fibers and contains a binder for the natural fibers. Advantageous additional developments of the invention are disclosed in the dependent claims.
One significant advantage of the invention can be seen in the fact that the tool carrier of the material processing tool is no longer manufactured from plastic, but rather to a significant degree from regrowing raw materials.
This results in a significantly easier disposal. If an incineration process is used, the carbon dioxide generated is, for example, practically compensated by utilizing regrowing raw materials. In addition, other disposal options may be considered, for example, composting.
According to the invention, it was surprisingly determined that tool carriers manufactured from materials with natural fibers have superior thermal and mechanical properties. Another positive aspect of the invention is that natural fiber materials can today be purchased and processed relatively inexpensive.
The tool carrier or the initially described objects have particularly advantageous mechanical and thermal properties if the fiber reinforcement is stabilized with a binder. The binder may consist of a customary binder that, for example, is available in the form of a suspension or a solid powder or granulate. Single-component or multi-component binders may be utilized. Organic or inorganic binders may be considered, for example, phenol resins, styrene resins, polycarbonates or polyolefins, in particular, polypropylene. A woven fiber fabric such as a knitted hemp, flax and/or sisal fabric that contains a solid binder can be compressed into the final shape under increased pressure and elevated temperature. During this process, the binder melts and is distributed in the woven fiber fabric such that a product with high stability and resistance to tearing is obtained. The natural fiber content may lie between 50% and 85%, preferably between 70% and 80%.
In another preferred embodiment, the tool carrier is entirely manufactured from natural materials. This allows a particularly simple disposal. For example, cellulose materials may be used as binders in this case.
Preferred embodiments of the tool carrier are characterized by the fact that the natural fibers consist of one or more of the materials hemp, flax or sisal.
Today, these materials are agriculturally produced in large quantities and consequently relatively inexpensive. In addition, they have favorable processing and stability properties.
In one particularly preferred embodiment, the tool carrier is manufactured from a granulate that consists of natural fibers and a binder, preferably polypropylene. The granulate can be produced in a particularly simple and inexpensive fashion. The grains of the granulate are melted and injected into a corresponding mold, e.g., as known from plastic injection molding. In this case, a particularly suitable mixture of the granulate respectively consists of 50% natural fibers and polypropylene.
Another preferred additional development of the material processing tool is characterized by the fact that the grinding and/or polishing element also is manufactured at least partially from natural fibers. This is also advantageous with respect to proper disposal of the worn-out material processing tool.